Fix selection of document Subjects via Spreadsheet having no effect

Steps to reproduce:

• User navigates inside Web UI to a folder with content.
• After clicking on Content View settings button, user selects Nature, Coverage and Subjects and then clicks Done
• User clicks on Spreadsheet Editor button and checks the Auto-save checkbox
• User double-clicks on one of the cells under Subjects and selects one of the values

Expected behaviour:

• The dropdown is closed and the cell has the selected value

Actual behaviour:

• The dropdown is closed and the cell is blank

Rainforest Video in attachments (after 3'50'')